Development of a Multi-Channel Low-Noise Microcurrent Data Acquisition System Based on ZYNQ

To meet the requirements for high-precision acquisition of multi-channel weak current signals in magnetic field tomography diagnostics for the CN-H1 star-simulator, this paper presents a 64-channel microcurrent data acquisition system based on the ZYNQ-7000 SoC. The system employs independent high-gain transimpedance amplification and filtering circuits for front-end conditioning. Utilising FPGA control over four AD4115 analogue-to-digital converters, it achieves parallel high-precision acquisition of 64 signals. Experiments demonstrate that within the ±2 μA input range, the system's equivalent input noise remains below 0.2 nA (RMS). The average effective number of bits (ENOB) per channel reaches 13.28 bits, with high inter-channel consistency (standard deviation of 0.04 bits). This system combines high channel density with outstanding single-channel measurement performance, making it suitable for precision measurement scenarios requiring parallel, high-precision acquisition of minute currents.